Crate executor_core 

executor-core

A flexible task executor abstraction layer for Rust async runtimes.

This crate provides unified traits and type-erased wrappers for different async executors, allowing you to write code that’s agnostic to the underlying executor implementation.

Overview

The crate is built around two main traits:

• Executor: For spawning Send + 'static futures
• LocalExecutor: For spawning 'static futures (not necessarily Send)

Both traits produce tasks that implement the Task trait, providing:

• Future implementation for awaiting results
• Task::poll_result for explicit error handling
• Task::poll_cancel for task cancellation

Quick Start

use executor_core::{Executor, init_global_executor, spawn};
use executor_core::tokio::TokioExecutor;

#[tokio::main]
async fn main() {
    // Initialize the global executor
    init_global_executor(TokioExecutor::new());

    // Spawn a task
    let task = spawn(async {
        println!("Hello from spawned task!");
        42
    });

    // The task can be awaited to get the result
    let result = task.await;
    println!("Task result: {}", result);
}

Features

• Zero-cost Executor Abstraction: Unified Executor and LocalExecutor traits using Generic Associated Types (GAT) to prevent unnecessary heap allocation and dynamic dispatch
• Type Erasure: AnyExecutor and AnyLocalExecutor for runtime flexibility
• Multiple Runtime Support: Tokio, async-executor, Web/WASM
• Task Management: Rich task API with cancellation and error handling
• No-std Compatible: Core functionality works in no-std environments
• Panic Safety: Proper panic handling and propagation

Lifetime Constraints

The current API requires 'static lifetimes for both futures and their outputs. This constraint comes from the underlying async runtimes and ensures memory safety when tasks may outlive their spawning scope. While this limits flexibility, it matches the constraints of most async runtime implementations in Rust.

Modules

async_executorasync-executor

Integration with the async-executor crate.

async_taskasync-task

Integration with the async-task crate.

tokiotokio

Integration with the Tokio async runtime.

webweb

Integration for Web/WASM environments.

Structs

AnyExecutor

A type-erased Executor that can hold any executor implementation.

AnyExecutorTask

Task type returned by AnyExecutor.

AnyLocalExecutor

A type-erased LocalExecutor that can hold any local executor implementation.

AnyLocalExecutorTask

Task type returned by AnyLocalExecutor.

CancelFuture

Future returned by Task::cancel().

DefaultExecutor

A default executor that uses the global and local executors.

ResultFuture

Future returned by Task::result().

Traits

Executor

A trait for spawning Send + 'static futures.

LocalExecutor

A trait for spawning 'static futures that may not be Send.

Task

A trait representing a spawned task that can be awaited, cancelled, or queried for results.

Functions

init_global_executor

Initialize the global executor for spawning Send futures.

init_local_executor

Initialize the thread-local executor for spawning non-Send futures.

spawn

Spawn a Send future on the global executor.

spawn_local

Spawn a future on the thread-local executor.

try_init_global_executor

Try to initialize the global executor for spawning Send futures.

try_init_local_executor

Try to initialize the thread-local executor for spawning non-Send futures.